In the Kiki series each cast member is given a food or drink item to sample while blindfolded. They must then sample a number of similar items and correctly identify the one they were given while blindfolded. Get it right and the cast member wins 100,000 yen (about US$1,000). Get it wrong and they receive a batsu (punishment), typically involving getting hit over the head with something.
In this episode they’re tasting Ponzu, a citrus-based sauce typically used for dipping.